This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. T-bet is the master regulator of Th1 T-cell differentiation and is critical to anti-viral immune response. We produced the first rough structural solution of the DNA-binding domain of T-bet in complex with an oligonucleotide of the consensus binding sequence, from crystals that diffracted to about 3.5 [unreadable]. The structure suggests a very interesting difference in the interaction mode of T-bet relative to other T-box binding proteins. Now, we have crystals from a number of different conditions that we hope will show improved diffraction. In addition, we have generated crystals of the protein bound to a variety of different DNA oligomers. We?re hopeful that this additional data could allow us to produce a much better model for this protein and proceed with publishing our findings.